Coolant circuit for engine with bypass line

ABSTRACT

A coolant circuit for cooling of an engine in a power system. The coolant circuit includes an inlet line and an outlet line. The coolant circuit further includes a heat exchanger with a plurality of heat exchanging elements. The coolant circuit also includes a bypass line disposed in parallel to the heat exchanger, between the inlet line and the outlet line. A control valve is disposed in the coolant circuit regulating the flow of a coolant, such that the coolant flows through the heat exchanger and the bypass line when the control valve is in a fully open position.

TECHNICAL FIELD

The present disclosure relates to a coolant circuit for an engine, and more particularly to a coolant circuit using a bypass line.

BACKGROUND

A coolant circuit for an engine may include a bypass line along with a heat exchanger. Based on the cooling load of the engine, the bypass line short-circuits a flow of the coolant through the heat exchanger when the demand on the coolant circuit for cooling the engine is low. U.S. Pat. No. 5,642,691 uses such a bypass line for short-circuiting the flow of the coolant through the heat exchanger.

SUMMARY

In one aspect, the present disclosure provides a coolant circuit for cooling of an engine. The coolant circuit includes an inlet line configured to receive a coolant from the engine. The coolant circuit further includes a heat exchanger connected to the inlet line for receiving the coolant. The heat exchanger is configured to remove heat from the coolant. An outlet line is provided in the coolant circuit to receive the coolant from the heat exchanger. The coolant circuit further includes a bypass line disposed between the inlet line and the outlet line. The coolant circuit also includes a control valve, such that the control valve allows the flow of the coolant through the bypass line and the heat exchanger, when the control valve is in a fully open position.

In another aspect, the present disclosure provides a method for cooling the engine. The method includes receiving the coolant from the engine into the inlet supply line, in fluid communication with the heat exchanger. The method further includes regulating flow of the coolant through the heat exchanger, in conjunction with the bypass line. The coolant passes through the heat exchanger and the bypass line when the control valve is in the fully open position. The method further includes passing the coolant from the heat exchanger and the bypass line to the outlet line and finally sending the coolant from the outlet line to the engine.

Other features and aspects of present disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic view of a power system having a cooling system;

FIG. 2 illustrates a schematic view of a coolant circuit with a control valve in a fully open position; and

FIG. 3 illustrates a process flow diagram for cooling the engine.

DETAILED DESCRIPTION

A power system 1 in which disclosed embodiments may be implemented is schematically illustrated in FIG. 1. The power system 1 may be a propulsion system including an engine 10 to drive a machine. The machine may include a marine ship, a power boat, or the like. Further, the engine 10 may be an internal combustion engine, such as, a petrol engine, a diesel engine, or a gas powered engine. The engine 10 may include a cylinder block 12 and one or more cylinder heads 14. The cylinder block 12 may include one or more cylinders disposed in any suitable configuration, such as, an inline arrangement, a radial arrangement, a “V” arrangement, to name a few.

The power system 1 further includes a cooling system 100 to cool the engine 10. The cooling system 100 may include a coolant circuit 200, a sea-water circuit 300, and a separate circuit 400. The coolant circuit 200, the sea-water circuit 300, and the separate circuit 400 may work in conjunction to cool the engine 10. The cooling system 100 may utilize power from the engine 10 for operation.

The coolant circuit 200 may be a closed-loop circuit associated with the engine 10. The coolant circuit 200 may include a supply line 202, a delivery line 204, and a heat exchanger 210. The supply line 202 and the delivery line 204 may allow a coolant to circulate in the coolant circuit 200. The coolant used in the coolant circuit 200 may include a mixture of water, antifreeze agent, and rust inhibiter. However, in various other embodiments, the coolant may include, for example, propylene glycol or ethylene glycol.

The heat exchanger 210 is connected to the supply line 202 through an inlet line 206. The inlet line 206 supplies the coolant to the heat exchanger 210 from the supply line 202. Further, the heat exchanger 210 may be connected to the delivery line 204 through an outlet line 208 to supply the coolant back to the engine 10. In an embodiment, the heat exchanger 210 may be located in close proximity to the engine 10. The heat exchanger 210 may be formed integrally with the engine 10.

The coolant circuit 200 further includes a coolant pump 220 provided in the delivery line 204. Alternatively, the coolant pump 220 may be disposed on the supply line 202. Based on a cooling load of the engine 10, a plurality of coolant pumps may be employed. The coolant pump 220 creates a pressure head to circulate the coolant in the coolant circuit 200. In an embodiment, the coolant pump 220 may be a centrifugal pump having a construction well known in the art.

The coolant circuit 200 may further include a control valve 230 disposed on either the inlet line 206 or the outlet line 208. In an embodiment of the present disclosure, the control valve 230 is disposed on the outlet line 208. The control valve 230 may be a three-way thermostatic valve. In an embodiment, the control valve 230 may be configured to be in either one of the two operating state, a fully open position or a closed position to control the flow of the coolant in the coolant circuit 200.

In an embodiment, the coolant circuit 200 includes a bypass line 240. The bypass line 240 is disposed between the inlet line 206 and the outlet line 208, fluidically coupling the inlet line 206 to the outlet line 208. Therefore, the bypass line 240 may provide an additional path for the flow of the coolant, in conjunction with the flow of the coolant through the heat exchanger 210. In an embodiment, the bypass line 240 may be a permanent tube defining an uninterrupted passage for the flow of the coolant when the control valve 230 is in the fully open position. In an embodiment, the bypass line 240 may be disposed in a parallel configuration with the heat exchanger 210. In another embodiment, the bypass line 240 may be integrated into the heat exchanger 210 or be any other type of passage fluidically coupling the inlet line 206 to the outlet line 208.

In an embodiment, the coolant circuit 200 may further include a service line 250, in addition to the bypass line 240. The service line 250 may also be disposed between the inlet line 206 and the outlet line 208. The service line 250 may provide an alternate path for the flow of the coolant when the control valve 230 is in the closed position. The service line 250 may short-circuit the flow of the coolant through the heat exchanger 210 as well as the bypass line 240.

The coolant circuit 200 may further include turbo unit 260 disposed in either the supply line 202 or the delivery line 204. The turbo unit 260 may increase the pressure of the coolant by using exhaust gases from the engine 10. Moreover, the engine 10 may be associated with an engine oil-cooler 270 to cool engine oil which is further used to carry heat away from the engine 10. The engine oil-cooler 270 may be coupled to the coolant circuit 200 to cool the engine oil. The coolant circuit 200 may also include an after-cooler 280. The after-cooler 280 may cool compressed air prior to be sent to the engine 10.

As illustrated in FIG. 1, the sea-water circuit 300 includes a sea-water pump 302 and a sea-water line 304. The sea-water pump 302 may provide feed to draw sea-water in the sea-water circuit 300. The sea-water line 304 may supply the sea-water to the heat exchanger 210 in the coolant circuit 200. In an embodiment, the sea-water circuit 300 may include a filtering arrangement (not illustrated) to filter the sea-water before passing through the heat exchanger 210.

In an embodiment, the separate circuit 400 may include a separate circuit pump 402 to circulate a cooling fluid. The separate circuit 400 may also include a separate circuit after-cooler 404 and an auxiliary heat exchanger 406. The auxiliary heat exchanger 406 may receive the sea-water from the sea-water line 304 to cool the cooling fluid. The separate circuit 400 may also include a valve 408 to control the flow of the cooling fluid.

FIG. 2 illustrates the coolant circuit 200, according to an embodiment of the present disclosure with the control valve 230 in the fully open position. The control valve 230 includes a housing 232 in which one or more thermostats 234 is disposed. The housing 232 may further include a plurality of ports 236 corresponding to each of the thermostats 234. In the illustrated embodiment, the control valve 230 may include an assembly of four thermostats 234 for each of the four ports 236. In other embodiments more or fewer than four thermostats 234 and ports 236 may be employed. The thermostat 234 may be configured to operate the control valve 230 in either a fully open position or a closed position. The thermostat 234 allows opening and closing of the port 236, which determines the operating state of the control valve 230, that is, the fully open position or the closed position.

The thermostat 234 responds to the temperature of the coolant flowing through the housing 232 in the control valve 230. In an embodiment, the control valve 230 includes a sealed wax pallet to control the movement of the thermostat 234 based on the temperature of the coolant. As illustrated in FIG. 2, when the control valve 230 is in fully open position, the thermostat 234 moves down resting on a seat 238 to open the port 236. This allows the coolant to flow through the port 236 to the delivery line 204. Further, the coolant may flow through the delivery line 204 to the engine 10 via the coolant pump 220.

As illustrated in the embodiment of FIG. 2, the heat exchanger 210 may be in connection with the cylinder head 14 of the engine 10 to receive the coolant through the supply line 202. Further, the heat exchanger 210 may be connected to the cylinder block 12 to supply the coolant through the delivery line 204. In an embodiment, the heat exchanger 210 may further be connected to the sea-water circuit 300 through sea-water line 304 for supplying and collecting the sea-water.

As illustrated in FIG. 2, the heat exchanger 210 may include a chamber 212 having a plurality of heat exchanging elements 214. The heat exchanging elements 214 may be of plate-type configuration, arranged in a stacked manner and parallel to each other in the chamber 212. Further, the chamber 212 may be sub-divided into two compartments, one for the flow of the sea-water and other for the flow of the coolant.

FIG. 2 further illustrates the bypass line 240 disposed between the inlet line 206 and the outlet line 208 of the coolant circuit 200. Specifically, the bypass line 240 may branch off from the inlet line 206 to fluidically connect with the outlet line 208. In an embodiment, the bypass line 240 may be formed integrally with the chamber 212 of the heat exchanger 210.

INDUSTRIAL APPLICABILITY

To meet the cooling requirement of the engine 10, the coolant circuit 200 of the present disclosure may employ a plate-type heat exchanger 210. In the heat exchanger 210, the heat exchanging elements 214 may be of plate-type configuration to provide a large surface area for effective cooling of the coolant. However, the plate-type heat exchanger 210 may also lead to high pressure drop in the coolant. The high pressure drop in the coolant may increase power consumption of the coolant pump 220 in the coolant circuit 200 which adds to an overall operating cost of the power system 1.

To minimize the pressure drop and still achieve considerably the same performance of the heat exchanger 210, the bypass line 240 is introduced in the coolant circuit 200. The bypass line 240 may allow for a larger heat exchanger 210 to be used which minimizes the pressure drop. The pressure drop across the heat exchanger 210 may create a pressure difference such that a portion of the coolant may pass through the bypass line 240. It may be understood that, the higher the pressure drop across the heat exchanger 210 the more the coolant flows through the bypass line 240.

Further, the coolant from the heat exchanger 210 at low pressure (due to pressure drop) and the coolant from the bypass line 240 at relatively high pressure may mix in the outlet line 208. This leads to an increase in the pressure of the coolant in the outlet line 208, and thus reduces the pressure head to be provided by the coolant pump 220 in the coolant circuit 200 which reduces the operating cost of the power system 1.

In the coolant circuit 200, the size of the bypass line 240 may vary depending on various parameters like the size of the heat exchanger 210, configuration of the heat exchanger 210, the engine cooling load, etc. The increase in the size of the bypass line 240 may result in lower pressure drop in the coolant and consequently reduced pressure head to be provided by the coolant pump 220. However, the size of the bypass line 240 may be selected to optimize the required pressure head and cooling performance in the heat exchanger 210. In an embodiment, the bypass line 240 may have a tubular structure having a diameter in a range of about 0.5 inches to 1.5 inches.

As illustrated in process flow 500 of FIG. 3, in step 502, the coolant at high temperature from the engine 10 is received by the inlet line 206. The coolant may be received from the cylinder head 14 in the engine 10 through the supply line 202. The supply line 202 may be in communication with the inlet line 206 for supplying the coolant to the heat exchanger 210.

Further in step 504, the flow of the coolant in the coolant circuit 200 is regulated by the control valve 230. The control valve 230 may switch to the fully open position or the closed position based on the temperature of the coolant. When the temperature of the coolant is above a threshold temperature, as described above, the thermostats may switch the control valve 230 to the fully open position. In the fully open position, the coolant flows through the heat exchanger 210 and the bypass line 240. When the temperature of the coolant is below the threshold temperature, the control valve 230 may switch to the closed position causing the coolant to flow through the service line 250.

Subsequently in step 506, the coolant from the heat exchanger 210 may be discharged into the outlet line 208. The coolant from the heat exchanger 210 may mix with the coolant from the bypass line 240. Further, the coolant from the heat exchanger 210 and the bypass line 240 is sent to the outlet line 208.

Finally in step 508, the coolant from the outlet line 208 is sent to the engine 10 via the delivery line 204. The coolant may flow to the engine 10 by the pressure head created by the coolant pump 220 in the coolant circuit 200. In an embodiment, the coolant may be received in the engine 10 by an engine jacket (not illustrated) enveloping the cylinder block 12. The coolant may flow in the engine jacket which extracts heat from the cylinder block 12 and thus cools the engine 10.

It will be apparent to those skilled in the art that various modification and variations can be made to the disclosed cooling system 100 and more particularly to the coolant circuit 200. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed system and method. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents. 

1. A coolant circuit for cooling an engine, the coolant circuit comprising: an inlet line configured to receive a coolant from the engine; a heat exchanger connected to the inlet line for receiving the coolant, the heat exchanger configured to extract heat from the coolant; an outlet line disposed between the heat exchanger and the engine, the outlet line configured to receive the coolant from the heat exchanger; a bypass line disposed between the inlet line and the outlet line; and a control valve to regulate the flow of the coolant, the control valve allows the coolant through the heat exchanger and the bypass line in a fully open position.
 2. The coolant circuit of claim 1, wherein the heat exchanger is a plate-type heat exchanger.
 3. The coolant circuit of claim 1, wherein the bypass line is integrated with the heat exchanger, fluidically coupling the inlet line and the outlet line.
 4. The coolant circuit of claim 1, wherein the bypass line is a tubular structure having a diameter in the range of about 0.5 inches to 1.5 inches.
 5. The coolant circuit of claim 1, wherein the control valve is a three-way valve.
 6. The coolant circuit of claim 1, wherein the control valve includes a thermostat configured to switch the control valve in at least one of the fully open position or a closed position.
 7. The coolant circuit of claim 1, wherein the control valve is in the fully open position when the temperature of the coolant is above a threshold temperature.
 8. A power system comprising: an engine; a coolant circuit for cooling the engine, the coolant circuit including: an inlet line configured to receive a coolant from the engine; a heat exchanger connected to the inlet line for receiving the coolant, the heat exchanger configured to extract heat from the coolant; an outlet line disposed between the heat exchanger and the engine, the outlet line configured to receive the coolant from the heat exchanger; a bypass line disposed between the inlet line and the outlet line; and a control valve to regulate the flow of the coolant, the control valve allows the coolant through the heat exchanger and the bypass line in a fully open position.
 9. The power system of claim 8, wherein the heat exchanger is a plate-type heat exchanger.
 10. The power system of claim 8, wherein the bypass line is integrated with the heat exchanger, fluidically coupling the inlet line and the outlet line.
 11. The power system of claim 8, wherein the bypass line is a tubular structure having a diameter in the range of about 0.5 inches to 1.5 inches.
 12. The power system of claim 8, wherein the control valve is a three-way valve.
 13. The power system of claim 8, wherein the control valve includes a thermostat to switch the control valve in at least one of the fully open position or the closed position.
 14. The power system of claim 8 further including a sea-water circuit to cool the coolant in the heat exchanger of the coolant circuit using sea-water.
 15. The power system of claim 14 further including a separate circuit.
 16. A method for cooling an engine, the method comprising: receiving a coolant from the engine by an inlet line in fluid communication with a heat exchanger; regulating flow of the coolant through the heat exchanger in conjunction with the bypass line by a control valve, the coolant passes through the heat exchanger and the bypass line when the control valve is in a fully open position; passing the coolant from the heat exchanger and the bypass line to the outlet line; and sending the coolant from the outlet line to the engine.
 17. The method of claim 16 further includes regulating the flow of the coolant to pass through a service line when the control valve is in a closed position
 18. The method of claim 16 further includes maintaining the flow of the coolant using a coolant pump.
 19. The method of claim 16 further includes passing sea-water through the heat exchanger.
 20. The method of claim 19 further includes maintaining the flow of the sea-water using a sea-water pump. 